When a brake is applied, a brake light is turned on to warn the appliance of a brake to the outside.
Conventionally, a method in which a sensor which is configured to detect the depression of a brake pedal is attached to a brake pedal and a brake light is turned on in accordance with a signal of this sensor is generally used. In such a method, there is a disadvantage in packaging a brake pedal, and since the sensor is disposed in a cabin, a noise problem may occur. Meanwhile, a method in which a brake light is turned on/off by detecting a movement of an input element which is activated in association with a depression of a brake pedal using a sensor which is mounted to a brake master cylinder has been introduced. However, there is a problem in that a mounting structure of a sensor to a master cylinder is complicated and there are other problems.